Rotary cutter



F. P. MILLER ROTARY CUTTER Feb. 1 3, 1934.

Filed Sept. l5, 1930 FRANK P. MILLER Patented Feb. 13, 1934 UNIrEo STATES PATENTl OFFICE RGTARY CUTTER Application september 16, i930 serial Ne. 482,327

11 Claims.

This invention relates to rotary cutters of the type in which inserted blades are employed.

Briey stated, the invention will be found to look to the provision of an inserted blade rotary 4l5 cutter of increased strength and decreased cost of manufacture as compared with other rotary cutters intended for the same purpose, these results being attained through the elimination of such separately made blade clamping devices as l screws, wedges and locking pins without, of course, a corresponding omission of function, it vbeing noted that no cutting away and consequent weakening of the material forming the head of the rotary` cutter is necessary for the accommodation of the blade clamping means embodied in this invention as is the case when screws, wedges, pins and the like are employed.

Another attribute of the invention resides in the means by which the blade may be adjusted to compensate for wear.

ther objects and advantages will be apparent during the course oi the following description.

In the accompanying drawing forming a. part of this application vand in which like numerals are'employed to designate like parts throughout the same,

Figure i is a fragmentary side elevation illustrating a preferred forni of cutter, parte being broken away,

Figure 2 is an end elevation of the cutter head with one blade and the contiguous portion of the cutter head shown in section,

Figure 3 is a vertical transverse sectional View 'taken on line 3-3 of Figure 1,

Y Figure e is an end elevation of the cutter head and several of the blades in place, the view illustrating that the blades are held securely in place by rolling or peening the adjacent portions of the material forming the head into engagement `with the blades,

Figure 5 is a perspective of a blade embodied in the invention,

Figure 6 is an end elevation illustrating a modification of the invention,

i5 Figure '7 is an end elevation illustrating a further modication of the invention,

Figure 8 is an end elevation illustrating another expression of the invention.

1n the drawing wherein for the purpose of il- 5o lustration are shown several preferred embodiments of the invention, the numeral 10 designates a shank terminating in a diametrically enlarged head l2. The head 12 is shown in Figure 1 to be provided with an annular series of spaced parallel longitudinally extending slots 14, the bot- (Cl. Tl-75.5)

tom walls oi which extend approximately parallel to the periphery of the head and at an angle to the axis of the head so that by the forward adjustment of the blades 16 positioned in the slots the cutting diameter of the tool is increased. *5.

Figures 2, 4 and 5 illustrate that each blade 16 is abruptly decreased in cross sectionalarea at a point between the inner and outer longitudinal edges thereof to define a lengthwise extending ledge or shoulder 20 preferably on the front or leading side wall thereof. As shown in Figure 4, the side walls of each blade receiving slot 14 are initially straight and are substantially parallel to each other and the ledges 20 are locatedk within the slots so that when the contiguous por- '7, tions of the material forming the head 12 are peened or rolled into rrn pressure and binding engagement with the ledges 2G for the full length thereof, the blades will be held securely in place against radial and endwise shifting. if,

By rolling or peening the portions of the head 12 ycontiguous to the ledges 20 into overhanging and pressure engagement with the ledges for the full length thereof retaining anges 22 are formed and as shown in Figures 1 and 3 the rear portions 80 of such flanges extend across the chamfered rear corners 24 of the blades to hold the blades against rearward movement in the slots thereof.

The rolling or peening of the peripheral portions of the head l2 into irrn binding engage- 85 ment with the ledges 20 of the blades forces the blades into firm seating engagement with the bottom walls of the slots. To provide for adjustment of the blades from time to time to compensate for wear and to restore the original cutting 90 diameter of the tool, it is merely necessary to drive the blades forwardly and then roll or poen additional portions of the head into engagement with the chainfered rear ends of the blades. With the blades thus advanced and secured in p1ace,- 95 the same may be reground in the usual manner.

Figure l and more particularly the blade shown in the lower portion of this ligure illustrates that the ledge 20 extends at an angle to the inner edge of the blade so that when the blade is driven'for- 100 wardly for adjustment purposes, the metal forming the associated retaining iiange 22 is crowded and hence is caused to more firmly hold the blade in place. Of course, the material forming the head 12 is suiiiciently ductile to allow the same to be worked without chipping while, on the other hand, the blades are made of a hard cutting metal.

The employment of the particular blade fastening means disclosed takes the place of the more 110 expensive separately made screws, wedges, fastening pins and the like employed in other cutters intended for the same purpose so that reduced cost of manufacture is attained. Also, the particular blade holding means embodied in this invention do not require the cutting away of substantial portions of the cutter head 12 torprovide for their accommodation and in this manner an increase in the unbroken cross sectional area of the cutter head is accomplished with a consequent increase in the strength of the reamer or other rotary cutter in which the invention is embodied.

In further adverting to the increased cross sectional area of the head 12, attention is invited to Figure 3 in which it is illustrated thatthe rear lower longitudinal corner of each blade is cut away or is bevelled to meet or nearly .meet the opposite longitudinal corner of the blade and the place of such material is taken by the material forming the head 12. Of course, this portion of -each blade is not called upon to bear a substam tial portion of the thrust incidenttotheoperation of the tool and hence the blade is in no way weakened. On the other hand, the head 12 is strengthened by the addition thereto of metal made possible by the cutting awayof the lower Arear longitudinal corners of the blades.

The cutter Vhead 12 may bedecreased in external diameter toward the rear portion `thereof to provide generous chipclearance and to maintain substantial parallelism between the peripheryof the head and the ledge 20, thereby simplifying `the peening or rolling operation.

Inthe form of invention illustrated in Figure 6, vthe body 30 of the rotary cutter is formed with a plurality of longitudinally extending slots 32 snugly receiving blades 34. The blades 34 are `provided in the leadingor forward sides thereof fth shallow grooves 36, the inner walls of which constitute ledges into pressure engagement with which the contiguous portions of the head 30 are rolled, peened'or `otherwise forced to hold the blades firmly in place against shifting both radially and endwise. .Of course, the rear portions of the iianges 38 defined by rollingorpeening portions of the head 30 into engagement with the blades areengaged with rthe chamfered rear ends of the blades to further hold the blades against endwise shifting. The side walls of the slots 32 are shown Ato converge slightly, and the side walls of the blades also converge inward for iiatcontact with the side walls of the slots. In .this case, the flanges 38 defined by rrolling or peening portions of the head 30 urge the converging side walls of the blades into firm pressure engagement withthe converging side wallsof the slots and the inner edges of the blades need not r.engage the bottom walls of the slots.

In the form of invention illustrated in Figure r1the head 40 is provided with an annular series of longitudinally extending slots 42 opening out throughthe periphery and forward ends thereof for the reception of blades 44, the side walls of ,the blades and the side walls of the slots being approximately parallel. The front or leading side ,of each blade is ,shown to be provided with a longitudinally extending groove 48 substantially semicircular in cross section and adapted for the reception of the contiguous peened portion of the material of the head so that the blade is held firmly in place against both radial and longitudinal shifting.

In that form of the invention illustrated in Figure 8, the head 50 is provided with an annular series of longitudinally extending slots 52 receiving blades 54 of a dissimilar metal. One side wall of each blade receiving slot 52 is shown to be rabbeted as indicated at 56 to provide for the reception of the longitudinally extending shoulders or ribs 58 of the opposed sides of the blades 80 54, the outer edge of the ribs defining ledges into engagement with which the contiguous portions of the material constituting the head 50 are rolled or peened with the result that the blades are held against axial and radial shifting. Of course, the rear ends of the blades are backed by the rear portions of the peened sections of the cutter head 50 and in this manner rearward movement of the blades under the strain of use is inhibited.

Like in the form of invention shown in Figures 1, 2, 3, 4 and 5, the blades shown in Figures "I and 8 have the lower rear longitudinal corners thereof cut away or bevelled to meet or nearly meet the opposite lower longitudinal corners of the blades to the end .that a greater unbroken cross sectional area of material forming the cutter head is allowed. Also, the cutter heads shown -in the various forms of invention may taper toward the rear ends thereof to provide increased chip clearance in the direction of the rear end of the head and at the same time to maintain substantial parallelism between the periphery of the head and the ledges into which the adjacent portions of the head are peened, rolled or otherwise .,105 forced, this latter feature greatly simplifying the peening or rolling operation.

Having thus described the invention, what is claimed is:

l. In a rotary cutter, a head having a slot, aiu() blade in said slot in advance of thev rear end thereof and having a ledge on one side thereof, that portion of the head contiguous to the ledge being pressed into binding engagement with Athe ledge and into that portion of the slot rearward ,11,5 ofthe blade for pressure and restrainingengagement with the rear end of the blade.

2. In a rotary cutter, ahead having va slot, a blade forwardly adjustable in saidslot and hav- .ing a ledge on one side thereof, thatportion 01.120

the head contiguous to the ledge being rolledinto binding engagement with the ledge to hold the blade against shifting, .the rolled portionof the cutter head being extended acrossa portion ,of the rear end of the blade to inhibit rearward ,125

vshifting of the blade.

3. In a rotary cutter, a head having a slot `diminished in depth toward the forward end thereof, a blade provided with a longitudinally extending ledge positioned within the slot, that portion of the head contiguous to .said ledge being rolled into pressure engagement with the ledge and about the rear end of the blade to hold the blade against endwise and radial shifting, said ledge being extended at an angle to the. inner edge of the blade, so that when the blade is moved forwardly during adjustment the rolled portion of the cutter head will be crowded and thereby caused to hold the blade more firmly in place.

4. In a rotary cutter, a head having an annular series of slots opening out through the periphery and forward end thereof, blades in said slots in advance of the rear ends thereof and abruptly decreased in cross sectional area at points be- 14 tween the inner and outer edges thereof to define ledges, portions of the material constituting said head being peened into pressure engagement with said ledges and into the rear portions of said slots for engagement with the rear ends of the blades to hold the blades in place.

5. In a rotary cutter, a head having an annular series of slots opening out through the periphery thereof, blades in said slots and abruptly decreased in cross sectional area at points between the inner and outer edges thereof to denne ledges, portions of the material constituting said head being peened into pressure engagement with said ledges and the rear ends of the blades to hold the blades in place, the rear portions of the blades being chamfered for contact by the peened portions of the material constituting the head.

6. In a rotary cutter, a head having an annular series of slots opening out through the periphery thereof, blades in said slots and abruptly decreased in cross sectional area at points between the inner and outer edges thereoi' to define ledges, portions of the material constituting said head being peened into pressure engagement with said ledges and the rear end of the blades to hold the blades in place, the major portions of said ledges being extended at angles to the inner longitudinal edges of the blades.

'7. In a rotary cutter, a head having a slot, a blade positioned in the slot and having one side wall thereof provided with a shallow groove extending out to the outer edge of the blade and dening a ledge, the portion of the material contiguous to said shallow groove being peened into said groove and into the slot at a point rearward of the blade for pressure and restrainving contact with the rear end of the blade.

8. In a rotary cutter, a head having a slot opening out through the periphery thereof and having one side wall thereof rabbeted to deiine a recess, a blade in said slot and having one side thereof provided with a lengthwise extending rib received in the recess defined by the rabbeting of one side wall of the slot, the peripheral portion of said head contiguous to said rib being rolled into pressure engagement with said rib and into the slot at a point rearward of the blade for pressure and restraining contact with the rear end of the blade.

9. In a rotary cutter, a head having an annular series of longitudinally extending slots having side walls and transversely inclined bottom walls extended at acute angles to the side walls, blades in said slots and having the inner rear longitudinal edge portions thereof bevelled to form flat angularly disposed bearing surfaces resting on said transversely inclined bottom walls, portions of said head being pressed into overhanging and retaining engagement with the blades and across the rear ends of the blades to secure the blades in position.

10. In a rotary cutter, a head having a. plurality of slots having bottoni walls extended at an angle to the axis of the cutter, blades in said slots and having ledges between the inner and outer edges thereof, portions of said head contiguous to said ledges being forced into binding engagement with said ledges, said head being decreased in diameter toward the rear end thereof to provide chip clearances increased in the direction of the rear end of the head and to provide substantial parallelism between said ledges and the periphery of the head.

11. In a rotary cutter, a head provided with a plurality of slots opening out through the periphery thereof, blades adjustable longitudinally in said slots and provided with ledges, portions of said head contiguous to said ledges being forced into binding engagement with said ledges, said ledges being extended at acute angles to the inner edges of the blades so that the pressure contact between the ledges and the contiguous portions of the head will be increased coincident with longitudinal adjustment of the blades.

FRANK P. MILLER. 

